Investigation of a control strategy toward series-to-parallel transition in a dual-motor hybrid electric vehicle

This study develops a control strategy for series-to-parallel transition in dual-motor hybrid electric vehicles, combining P1 motor-based open-loop engine torque regulation with P3 motor-governed closed-loop torque control to ensure seamless mode transitions under both steady and dynamic conditions. Experimental validation demonstrates consistent 1.8-s transition durations at 60 km/h with jerk levels below 10 m/s 2 in steady state. During dynamic operation, the control strategy reduces peak jerk by 54% (19.37–8.84 m/s 2 ) in series-to-parallel transitions and accelerates power response by 42% (0.81 s–0.47 s) in parallel-to-series transitions, improving transition smoothness and drivability directionally.